Table Of Content
Beautiful Architecture
Edited by Diomidis Spinellis and Georgios Gousios
Beijing • Cambridge • Farnham • Köln • Sebastopol • Taipei • Tokyo
Beautiful Architecture
Edited by Diomidis Spinellis and Georgios Gousios
Copyright © 2009 O’Reilly Media. All rights reserved.
Printed in the United States of America.
Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472.
O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also
available for most titles (http://safari.oreilly.com). For more information, contact our corporate/institutional
sales department: 800-998-9938 or [email protected].
Editor: Mary Treseler Indexer: Fred Brown
Production Editor: Sarah Schneider Cover Designer: Karen Montgomery
Copyeditor: Genevieve d’Entremont Interior Designer: David Futato
Proofreader: Nancy Reinhardt Illustrator: Robert Romano
Printing History:
January 2009: First Edition.
O’Reilly and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. Beautiful Architecture and
related trade dress are trademarks of O’Reilly Media, Inc.
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as
trademarks. Where those designations appear in this book, and O’Reilly Media, Inc. was aware of a trademark
claim, the designations have been printed in caps or initial caps.
While every precaution has been taken in the preparation of this book, the publisher and authors assume no
responsibility for errors or omissions, or for damages resulting from the use of the information contained
herein.
ISBN: 978-0-596-51798-4
[M]
1231531335
All royalties from this book will be donated
to Doctors Without Borders.
CO NTEN TS
FOREWORD ix
by Stephen J. Mellor
PREFACE xiii
Part One ON ARCHITECTURE
1 WHAT IS ARCHITECTURE? 3
by John Klein and David Weiss
Introduction 3
Creating a Software Architecture 10
Architectural Structures 14
Good Architectures 19
Beautiful Architectures 20
Acknowledgments 23
References 23
2 A TALE OF TWO SYSTEMS: A MODERN-DAY SOFTWARE FABLE 25
by Pete Goodliffe
The Messy Metropolis 26
Design Town 33
So What? 41
Your Turn 41
References 42
Part Two ENTERPRISE APPLICATION ARCHITECTURE
3 ARCHITECTING FOR SCALE 45
by Jim Waldo
Introduction 45
Context 47
The Architecture 51
Thoughts on the Architecture 57
4 MAKING MEMORIES 63
by Michael Nygard
Capabilities and Constraints 64
Workflow 65
Architecture Facets 66
User Response 87
v
Conclusion 88
References 88
5 RESOURCE-ORIENTED ARCHITECTURES: BEING “IN THE WEB” 89
by Brian Sletten
Introduction 89
Conventional Web Services 90
The Web 92
Resource-Oriented Architectures 98
Data-Driven Applications 102
Applied Resource-Oriented Architecture 103
Conclusion 109
6 DATA GROWS UP: THE ARCHITECTURE OF THE FACEBOOK PLATFORM 111
by Dave Fetterman
Introduction 111
Creating a Social Web Service 117
Creating a Social Data Query Service 124
Creating a Social Web Portal: FBML 133
Supporting Functionality for the System 146
Summation 151
Part Three SYSTEMS ARCHITECTURE
7 XEN AND THE BEAUTY OF VIRTUALIZATION 155
by Derek Murray and Keir Fraser
Introduction 155
Xenoservers 156
The Challenges of Virtualization 159
Paravirtualization 159
The Changing Shape of Xen 163
Changing Hardware, Changing Xen 169
Lessons Learned 172
Further Reading 173
8 GUARDIAN: A FAULT-TOLERANT OPERATING SYSTEM ENVIRONMENT 175
by Greg Lehey
Tandem/16: Some Day All Computers Will Be Built Like This 176
Hardware 176
Mechanical Layout 178
Processor Architecture 179
The Interprocessor Bus 184
Input/Output 184
Process Structure 185
Message System 186
File System 190
Folklore 195
The Downside 195
vi CONTENTS
Posterity 197
Further Reading 198
9 JPC: AN X86 PC EMULATOR IN PURE JAVA 199
by Rhys Newman and Christopher Dennis
Introduction 200
Proof of Concept 202
The PC Architecture 205
Java Performance Tips 206
Four in Four: It Just Won’t Go 207
The Perils of Protected Mode 210
Fighting A Losing Battle 214
Hijacking the JVM 217
Ultimate Flexibility 229
Ultimate Security 231
It Feels Better the Second Time Around 232
10 THE STRENGTH OF METACIRCULAR VIRTUAL MACHINES: JIKES RVM 235
by Ian Rogers and Dave Grove
Background 236
Myths Surrounding Runtime Environments 237
A Brief History of Jikes RVM 240
Bootstrapping a Self-Hosting Runtime 241
Runtime Components 246
Lessons Learned 259
References 259
Part Four END-USER APPLICATION ARCHITECTURES
11 GNU EMACS: CREEPING FEATURISM IS A STRENGTH 263
by Jim Blandy
Emacs in Use 264
Emacs’s Architecture 266
Creeping Featurism 272
Two Other Architectures 275
12 WHEN THE BAZAAR SETS OUT TO BUILD CATHEDRALS 279
by Till Adam and Mirko Boehm
Introduction 279
History and Structure of the KDE Project 282
Akonadi 287
ThreadWeaver 303
Part Five LANGUAGES AND ARCHITECTURE
13 SOFTWARE ARCHITECTURE: OBJECT-ORIENTED VERSUS FUNCTIONAL 315
by Bertrand Meyer
Overview 315
CONTENTS vii
The Functional Examples 318
Assessing the Modularity of Functional Solutions 321
An Object-Oriented View 330
Assessing and Improving OO Modularity 336
Agents: Wrapping Operations into Objects 341
Acknowledgments 345
References 346
14 REREADING THE CLASSICS 349
by Panagiotis Louridas
Everything Is an Object 353
Types Are Defined Implicitly 361
Problems 367
Brick and Mortar Architecture 372
References 380
AFTERWORD 383
by William J. Mitchell
CONTRIBUTORS 387
INDEX 393
viii CONTENTS
